Hydraulic pump and motor



Aug. 15, 1950 F. E. sTAATs HYDRAULIC PUMP AND MOTOR m W m w m a s, a m a w i 6 M3 mm Tw I. w

mh mb mw .w MN w mm W W w Mms Aug' 15, 1950 F. E. s'rAATs 2,518,-830

HYDRAULIC PUMP AND MOTOR Filed Oct. 15, 1947 6 Sheets--Shee'l'I 3 Aug- 15, 1950 F. E. STAATS 2,518,83o

ug 15, 1950 F. E. sTAATs 2 ,5l8,830

HYDRAULIC PUMP AND MOTOR Filed Oct. 15, 1947 6 Shee't'S-Sheet 6 gwna/MM i Patented Aug. 15, 1950 UNITED sT-ATEs PATNT, OFFICE Applicflonzclt-oi: No. 780,057

This invention relates to hydraulic Duml and motors and more particularly to an improve'd hydraulic pump having a variable throw crankshaft and pressure responsive means associated with the output of the pump for eifecting changes in the crankshaft throw.

It is an4 object of this invention to provide an improved pump of the kind to be more specifically described herein'after having radially disposed pumping oylinders with pistons connected to a common crank pin and valves for each cylinder operated by means connected to a orank pin fixed to the piston crank pin and eocentric thereto.

Another object of this invention is to provide radial hydraulic pump having a drive shaft with a movably mounted double ecoentric crank pin and' a piston about the orankshaft operative to vary the eocentrioity of the orank pin relative to the axis of the crankshaft. The crank pin operating piston is so construoted and arranged that its movement will be aifected by the demand for maintaining a constant output pressure.

A further object of this invention is to provide a constant speed pump for delivering a constant pressure, the pump being so constructed that variations in demand will affect the stroke of the pumping pistons to maintain a substantially equal output pressure.

A further object of this invention is to provide a oonstant speed pump for automatically delivering a variable pressure, the pump being so constructed that variations of the load will ail'ect the stroke of the pumping pistons and automatically furnishing the proper output pressure.

Yet another object of this invention is to provide a valve Operating means directly associated with the erank pin of the radial pump for operating the valves in synohronism with the rotation of the crank pin in all positions of the crank pin relative to the axis of the drive shaft.

With the above and other objects in view, my e Figure 5 is a fragmentary detailed section taken on the line 5-5 of Figure 1,

Figure 6 is a fragmentary section taken on the line 6-6 of Figure 1,

Figure 7 is a fragmentary transverse section partly broken away, taken on the line 1--'| of Figure 1,l

Flgure 8 isaa transverse section taken on the line 8-8 of Figure 1,

,Figure 9 is a fragmentary detailed section taken on-the line 9-9 of Figure 1,

Figure 10 is a plan view of the looking ring removed from the pump,

Figure 11 is a fragmentary enlarged detailed section of the looking ring and nut on the drive shafts,

Figure 12 is a longitudinal section of a modifled form of this invention as related to a 'liquid driven engine. i

Referring to the drawings, the numeral 20 designates generally a hydraulic pump which is adapted to be driven at a oonstant speed and is provided with means for maintaining the output pressure at a oonstant pressure irrespeotive of the use of the outlet fluid and for maintaining a constant fluid pressure whether units driven by the pump are being operated or not.

' 'I'he pump 20 is formed of a substantially hemispherioal housing 2| open at one end and a cover plate or closure 23 for closing the open end. A ciroumferentially disposed inlet passage is formed in the housing 2| substantially in the center thereof, and an annular ciroumferentially dispposed outlet passage is formed in the housing rearwardly of the inlet passage.

The housing 2| is also formed with a series of forwardly opening bores 25 near the front end thereof for supporting osoillating valves therein. The inlet passage 22 and outlet passage 2| are oommunicated with the valve bore 25 by forwardly extending passages 26 and 21 respeotively. The inlet passage 26 between the valve bore 25 and the passage 22 extends forwardly to communicate with the front end of the valve. The outlet passage 21 between the passage 24 and the bore 25 terminates in the bore 25 adjacent the rear end thereof. t

A valve 28 is rockably supported within the bore 25 in an apertured sleeve or bearing 29. The bearing 29 is fixed in the bore 25 and formed with circumferentially disposed openings 30 which open into the inlet passage 26. The valve 28 is formed of a tubular sleeve 3| rotatable in the bearing 29 and extending along the length there- 01-. The valve sleeve 3| is formed with a Vertical 3 Wall 32 intermediate the length thereof for separating the inlet and outlet chambers communicating therewith,

The sleeve 3| is formed with an opening 34 on one side thercof communicating with the opening 30 in the sleeve 29 for admitting the fluid from the inlet passage to the valve. The sleeve 29 is formed with openings 35 opening into a passage 36 which extends from the valve to the cylinders 31 in the housing 2|. The sleeve 3| is formed with openings 38 which are adapted to register with the openings 35 in one position of the sleeve 3| for permitting the flow of fluid from the inlet passages to the cylinder.

The opening 34 is adapted to register with the opening 30- in the sleeve 29 for permitting a flow of fluid therethrough in all positions of the valve 28. The inlet openings of both the sleeve 29 and sleeve 3| are disposed forwardly of the central wall 32 of the valve. The valve 28 rearwardly of the wall 32 is formed with openings communicating with the outlet of the pump. The sleeve 3| rearwardly of the wall 32 is formed with openings 39 which are adapted to register with openings 40 in the bearing 29 to provide an outlet port or valve for the cylinder.

An opening 4| in the sleeve 3| is adapted to register with an opening 42 in the sleeve 29 for providing an outlet for the fluid from the cylinder through the valve 28 into the outlet passage 21. An externally opening outlet passage 44 is formed in the housing 2| at the top thereof, communicating with the annular outlet passage 24.

The passage 44 is adapted to be connected by suitable fluid conducting pipes to hydraulically operated devices. The radially disposed cylinders 31 formed in the housing 2| are each communicated with the inlet and outlet passages of the pump 20 by valves and passages as described above.

Pistons 45 are slidably disposed in each of the cylinders 31 and are connected to a central bearing 46 in a recess 41 at the front end of the housing 2|. One of the pistons 45a is considered the master piston and is connected to the main bearing 46 by a connecting rod 48 which is pivotally connected to the piston by a pin 49 and fixed on the bearing 46 as by the pin 50. The remaining pistons 45 are connected to the main bearing 46 by connecting rods which are pivotally connected to the piston by pins 52 and pivotally connected to the bearing 46 by pins 54.

The connecting rods 5| are designated as articul-ated rods while the rod 48 is designated as a master connecting rod. The valve sleeves 3| are extended forwardly beyond the front end of the pump body 2| and are adapted to engage in recesses in the cover 22. The valve 28 is supported in the housing 2| and cover 22 by roller bearings as 55.

A transverse or diametric opening is provided in the valve 28 forwardly of the housing 2| in the space between the front end of the housing and the cover 22. A valve operated pin 56 is slidably disposed through the opening 51 in the valve. The valve pin 56 is pivotally connected to a bearing 51 to be operated in conjunction with the main bearing 46 described above.

A pin 56 is provided for each of the valves 28, and one of the pins 56a is constructed as a master pin, while the other pins 56 are pivotally connected to the bearing 51 as articulated pins. The bearing 51'is provided with a pair of radially extending longitudinally spaced apart fi-anges 58 about the center hub 59. The pins 56 are pivotally connected by the bearing 51 by pins 60 engaglng through the flanges 58. The master pin 56a extends inwardly beyond the pin into an arcuate recess 6| in the hub 59.

The extension 62 of the pin 56a is adapted to engage in the arcuate recess 8| for permitting the master pin 56a a certain degree of rocking movement for timing the valves in relation to the crankshaft and in relation to the pistons of the pump.

As the bearing 51 is caused to rotate by the drive shaft which also oscillates the mam bearing 48, the valve movement will be offset in a deflnite timlng relation as the master pin 56a is rockd to an extreme position in the slot or recess When the extension 62 engages the edge of the recess 6|, all of the valves will be actuated in timed relation to the pistons with the desired lag furnished by the size of the recess 6|.

A crankshaft 10 is provided in the pump 20 for reciprocating the pistons 45 and actuating the valves 28. The crankshaft 10 is adapted to be rotated at a constant speed from an extemal source of power, and is formed of a drive shaft 1| and a driven shaft 12 connected at the front end thereof.

The front or driven shaft 12 is mounted eccentric to the drive shaft 1|. The drive shaft 1| is rotatably supported in the rear end 14 by bearings 15, and a sealing member 16 is carried by the cover 14 between the bearing 15 and the opening through which the drive shaft 1| extends. The drive shaft 1| extends forwardly substantially to the center of the, housing 2| where it is formed with an enlarged disk 11 thereon. A hollow or tubular connecting member 18 is fixed to the disk 11 by recessed screws 19 or other suitable fastening devices, and extends forwardly of the disk 11.

The connecting member 18 is eccentric to the shaft 1|. The forward end of the sleeve 18 is reduced in diameter as at 80, and roller bearings 8| journal the reduced end of the connecting member in the housing 2 I. The connecting member 18 is rtated with the drive shaft 1|, and is further connected thereto by keys 82 engaging in keyways 84 of a forwardly extending reduced diameter sleeve 85 fixed to the front end of the disk 11 within the connecting member 18. The opening in the sleeve 18 adjacent the drive shaft 1| is enlarged for` housing the enlarged end of the driven shaft 12, and the outer end of the sleeve 18 is reduced to form a bearing for the intermediate portion 86 of the driven shaft. The driven shaft 12 is disposed eccentrically to the drive shaft 1|, in the connecting member 18.

The intermediate portion 86 of the d'riven sha'ft 12 is rotatably journaled in a bushing 81 carried by the connecting member 18 in the outer end thereof. The enlarged end 88 of the driven shaft 12 is disposed immediately adjacent to the disk 11, fixed on the drive shaft 1|. The enlarged portion 88 is formed with helical keyways 89 therein, for engagement with means to be later described, for rotating the driven shaft relative to the drive shaft. The end of the driven shaft 12, adjacent the drive shaft 1|, is journaled in a bearing 90 fixed in the disk 11. A bearing 9| is provided about the intermediate portion 86 of the driven shaft within the connecting member 18. A crank pin 92 is fixed to or formed on the forward end of the drriven shaft 12 c eccentric thereto. The crank pin 92 is provided the main crank 'pin 02 set in a bearing 06 carried by the center of the bearing 51. .The offset 95 is disposed eccentric to the axis of the cr'ank pin 92, and offset'eccentrically relative tofthe longitudinal axis of the driven shaft 076.

,As thus .far described, the driven shaft 12 Is free to rotate relative to the drive shaft 1|. For rotation of the driven shaft by the drive shaft,

'a connecting member I00 is provided. The connecting member I00 is formed of a sleeve I0| disposed about the drive shaft 1|, rearwardlyv of the disk 11. The sleeve I0| is rotatably mounted on a bushing I02 about the shaft 1|. 'A'disk IM is fixedon the front end of the sleeve IOI and a pair of forwardly extending arms I05 are fixed to 'or formed on the forward side of the disk I0l.

lmember I00 is limited only by the engagement of the keys I01 in the splines 89. As the connecting member I00 is moved along the axis of the drive shaft 1|, the engagement of the keys I01 in the helical splines 89 causerotation of the driven shaft 12 relative to the drive shaft 1|.

As the driven shaft 12 is rotated relative to the axis of the drive shaft 1I, the crank pin 92 and at the outer end thereof. for oscillating the bearing 01. The valve operating bearing 51 is oscillated 'by rotation of the ofloffset 05 are moved radially relative to the axfs of the drive shaft 1|,v by virtue of the eccentric disposition of the driven shaft 12.

The pump 20- is designed so that a constant pressure will be delivered from the pump while the drive shaft 1I is turned at a constant speed. In order to vary the output pressure while the shaft 1I is rotating constantly, it is necessary to rotate the driven shaft 12 to a position where the movement of the pistons 45 in the cylinders 31 will be reduced or enlarged according to the requirements of the output pressure. As the driven shaft 12, is rotated by sliding movement of the connecting member |00 on the drive shaft 1 I, the axis of rotation of the crank pin 92 and offset 95 is moved inwardly and outwardly for varying the throw of the pistons. In order to provide for the automatic movement of the driven shaft relative to the drive shaft in relation to the output pressure, there is provided an Operating cylinder IIO in the rear end of the housing 2|, connected to the connecting member |00. The cylinder I I0 is disposed concentrically about the drive shaft 1| and is journaled about the connecting member I00 by thrust bearings III and II2. 4

The outer race of the bearings I II and II2 are carried by the piston IIO, and the inner race is carried by the connecting member I00. The bearings III and II2 are so constructed and arranged that the connecting member I00 is free to rotate within the piston I I0, and axial movement of either the connecting member I00 or the piston |I0 will effect sliding movement of the other. Springs I I4 'are provided between the rear end of the piston IIO and the inner surface of the rear .cover 14. The Springs IM constantly bias the piston forwardly in the cylinder I I5. Piston rings I IS are provided about the piston I I0 for engageauaeao -ment with the cylinder walls -I Il for sealing the piston therein.

The cylinder III is provided with an annular recess or groove II1 about the rear end thereof, and the piston II. is provided with an enlarged shoulder I II in slidable engagement with the wall of the enlarged portion II1. The space between the reduced end of the cylinder I IS and the shoulder I I! on the piston provides the chamber about the piston I IO into which pressurized fiuid is adapted to be contained for sliding the piston I I0 against tension of the springs III. The housing 2| is formed witha passage I20 between the outlet passage 24 and the chamber I I9 formed about the piston IIO, for admitting fiuid under pressure into the chamber for exerting a force against the shoulder IIO. A nut I2I is'provided for engagement about the sleeve IOI for securing the bearings II'I and II2 on the member I00 about the shaft 1|.

The nut' I 2| is locked against rotation by a lock washer I22 engaging in a/recess I24-in the sleeve IOI, and in the recess I25 in the periphery of the nut. A lug I20 is formed on the outer periphery of the looking ring I22 for/engagement in the recess of the nut and an inwardly extending lug I21 is formed on the ring I22 for engagement in the recess I2l.

In the use and operation of this pump 20, fiuid is admitted through a boss I28 on the side of the housing 2| into the inlet passage 22. The fiuid then flows through the passages 26 into the valve 28; from the valve 28 the fiuid fiows through the passage 38 into the cylinders 31. Leaving the cylinders 31 under pressure, the fiuid fiows through a passage 43 into the valve 28.

The fiuid then ilgws'out the passages 21 and 24. The fluid is contained also within the passage I20 and in the chamber IIS under the outlet pressure. The desiredvpressure which is to be maintained by the pump is determined by the tension of the Springs IM. As the Outlet pressure decreases, the Springs IH will slide the piston IIO forwardly carrying with it the connecting member I00 which in turn will rotate the driven shaft 12 relative to the drive shaft 1|, for increasing the stroke of the pistons 45.

Rotation of the driven shaft 12 will effect the radial displacement of the crank pin 92 relative to the axis of the drive shaft 1| so that a greater throw is provided for the pistons 45. Since the drive shaft 1| is rotating at a constant speed, an increase in the length of the stroke of the pistom 45 will decrease the pressure output. This will then increase the volume and decrease the pressure output.

Similarly, as the output pressure increases, the piston |I0 will be moved rearwardly and the stroke of the pistons 45 will be shortened so that less fluid is pumped from the cylinders 31 while the crankshaft 10 is ro'iating at a constant speed.

In Figure 12 there is shown a modified form of this invention which is particularly applicable to a motor to be driven by a pump of this kind.

The motor M0 is formed of a housing 2| a similar to the housing 2| of the pump 20. Annularly disposed inlet and outlet passages 23a and 24a, are formed in the engine M0 and are connected to the cylinders 31a through valves 28a, similar to the valves described in the pump above.

The drive shaft 10a of the motor I40 is formed in one piece, having an offset crank pin 92a, and an offset 95a for separating the valves 28a. The operation and construction of the valves 28a is identical to the construction and operation described above for the pump 20.

No means is provided in the motor M for varying the throw of the crank pins as the demand from the motor' will be taken care of and Satised by the automatic control in the pump 20 which is adapted to furnish the proper pressure in the lines between the pump 20 and the motor M0, causing the motor to deliver the proper torque at the proper speed of the load for the input horse power.

I do not mean to confine myself to the exact details of construction herein disclosed, but claim all variations falling within the purview of the appended claims.

Having thus described my invention, what I claim is:

1. A constant speed and constant deliverypressure pump comprising a housing, cylinders in said housing, pistons slidable in said cylinders, a crankshaft journaled in said housing, said housing formed with inlet and o'utlet passages communicating with said cylinders, said crankshaft including a drive shaft, a driven shaft eccentric to said drive shaft, a slidable coupling between said latter shafts, a bearing member for said crankshaft concentric to said drive shaft about said driven shaft and `journaled in said housing, an eccentric crank pin on said driven shaft extending beyond said bearing member, a helical sliding connection between said driven shaft and said coupling whereby said driven shaft will be rotated in said bearing member and circumferentially displaced relative to said drive shaft upon sliding of said coupling, and means actuated by the fiuid outlet pressure for sliding said coupling thereby varying the crank pin relative to the axis of the crankshaft.`

2. A constant speed and constant deliverypressure pump comprising a housing, cylinders in said housing, pistons slidable in said cylinders, a crankshaft journaled in said housing, said housing formed with inlet and outlet passages communicating with said cylinders, said crankshaft including a drive shaft, a driven shaft eccentric to said drive shaft, a slidable coupling between said latter shafts, a bearing member concentric to said drive shaft about said driven shaft and rotatable in said housing, an eccentric Crank pin on said driven shaft extending beyond said bearing member, said driven shaft formed with a helical groove thereabout, a coupling member slidable on said drive shaft and engaging in said groove whereby said driven shaft will be rotated in said bearing member upon sliding of said coupling member, a cylinder in said housing about said drive shaft, said housing formed with a passage between said latter cylinder and said Outlet pas'sage, a spring-pressed piston in said latter cylinder fixed on one end of said coupling member, and opposed thrust bearings carried by said latter piston and said coupling member for sliding said latter piston and said coupling together while permitting the rotation of drive shaft therein.

3. constant speed and constant deliverypressure pump comprising a housing, cylinders in said housing, pistons slidable in said cylinders, a crankshaft journaled in said housing, said housing formed with inlet and outlet passages communicating with said cylindersI said crankshaft including a drive shaft, a driven shaft eccentric to said drive shaft, a slidable coupling member on said drive shaft, a bearing member concentric to said drive shaft about said driven shaft and journaled in said housing, an eccentric crank pin on said driven shaft extending beyond said bearing member, said driven shaft formed with a spiral groove within which said coupling member is engaged whereby said driven shaft will be circumferentially displaced relative to said drive shaft upon sliding of said coupling member, a cylinder in said housing about said drive shaft, said housing formed with a passage between said latter cylinder and said outlet passage, a spring-pressed piston in said latter cylinder, and opposed thrust bearings carried bv said latter piston and said coupling member for sliding said latter piston and said coupling member together while permitting the rotation of said coupling member therein, whereby an increase of pressure in said Outlet passage caused by'decrease in demand will effect sliding of said latter piston against the spring tension for decreasing the throw of said pistons and decreasing the volume and outlet' pressure of said pump.

4. A constant speed and constant-deliverypressure pump comprising a housing, radially disposed cylinders in said housing, pumping pistons slidable in said cylinders, a crankshaft including a drive shaft and a driven shaft, a driven shaft bearing in said housing concentric with said drive shaft, said driven shaft rotatably engaging in said bearing eccentric thereto, a coupling member slidable on said drive shaft engaging in a helical groove on said driven shaft, a crank pin on said driven shaft and a main bearing on said crank pin connected to said pistons, a spring-pressed piston slidable on said drive shaft connected to said coupling member, said housing formed with an outlet passage from said cylinders communicating with a cylinder about said drive shaft for sliding said latter piston in response to variations in demand thereby rotating said driven shaft in said bearing and rocking said crank pin radially relative to the axis of said drive shaft and driven shaft bearing for varying the throw of said pumping pistons.

FRANKLIN E. STAATS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED ST-ATES PATENTS Number Name Date 172,904 Anthony Feb. 1, 1876 1,010,902 Hansen Dec. 5, 1911 1,137,877 Manly, et al. May 4, 1915 1,212,791 Manly Jan. 16, 1917 1,283,249 Manly Oct. 29, 1918 1,630,168 Cant May 24, 1927 FOREIGN PATENTS Number Country Date 6,945 Switzerland 1893 366,097 Italy 1938 710,643 France 1931 

